1. Field of the Invention
The present invention relates to a transmission mounted in a vehicle.
2. Description of the Related Art
Heretofore, various kinds of transmission systems have been used in a drive system of a vehicle, including manual transmission (hereinafter referred to as “MT”) systems in which a driver changes a transmission gear by driving a shift actuator by using a clutch pedal (clutch lever) and a shift pedal (shift switch).
Automatic transmission (“AT”) systems are transmission systems in which a shift actuator is automatically driven, and a transmission gear is changed according to the speed, engine rotation speed, or the like of a vehicle.
Among the AT systems, torque converter ATs that use a combination of a torque converter and a planetary gear and perform automatic gear change by hydraulic control are most popularly used in vehicles. In a torque converter AT, gear change timing is precisely set based on various factors such as adjustment of accelerator depression, vehicle speed, and so forth by computer control.
Automated manual transmission (“AMT”) systems are transmission systems in which only clutch operation is automated and a shift pedal (shift switch) is operated in the same manner as that of MT systems. AMT systems are also called semi-automatic transmission systems.
In AT systems or AMT systems, clutch operation at the time of starting is automatically performed in a simplified manner as compared with MT systems. MT systems are also called “3-pedal mode” since the transmission is operated in MT systems by using three pedals including an accelerator pedal (accelerator grip), a brake pedal, and a clutch pedal (clutch lever). Meanwhile, AT systems and AMT systems are called “2-pedal mode” since AT systems and AMT systems do not require clutch pedal (clutch lever) operation, and the transmission is operated by using two pedals including an accelerator pedal (accelerator grip) and a brake pedal.
Today, AMT systems mounted in passenger cars also automatically perform gear selection by controlling accelerator opening and clutch and gearbox actuators through by-wire control (electronic control). Furthermore, a dual clutch automated manual transmission (DCT), which is an automatic transmission that includes a clutch including two power transmission paths, is also known as a transmission.
Japanese Patent Publication No. 4150481 discloses a motorcycle in which a transmission system can be selected from a semi-automatic transmission system and a fully automatic transmission system.
However, Japanese Patent Publication No. 4150481 does not disclose the timing and conditions of switching the transmission system.